Even Durst completely shut down true pro enlarger mfg some time back, though they still market less expensive enlargers up to 4x5.
Some of the old units, if well care for, should last a century, and with declining demand by pro labs per se, I guess there just isn't much profit in it anymore, if any. The cost of the materials and skilled labor has skyrocketed since they heyday or many of these classic units. Nowdadays a lot of anodized aluminum and automated CNC machining is used in manufacture instead. Market prices vary for enlargers in general. Sometimes you
can pick up a hundred thousand dollar enlarger for downright free if you're patient. But these little Leitz ones are probably even less common!